Adverse drug events in nursing homes: Common and preventable

Medication-related injuries in nursing homes are common and often preventable according to authors of the largest study to date evaluating adverse drug events due to medication errors in U.S. nursing homes.

More than half of the 546 medication-related injuries that were identified in a study of 18 community nursing homes were preventable, according to Jerry H. Gurwitz, M.D., from the Meyers Primary Care Institute, a joint initiative of the University of Massachusetts Medical School and the Fallon Healthcare System in Worcester, Massachusetts. The Massachusetts nursing home study, titled "Incidence and Preventability of Adverse Drug Events in the Nursing Home Setting," was published in the August 1, 2000, issue of the American Journal of Medicine .

"This important study demonstrates that adverse events related to drug therapy continue to be a common, and perhaps preventable source of illness in nursing home residents," said Darrell Abernethy, M.D., Ph.D., Clinical Director of the National Institute on Aging. "It reinforces the necessity of putting prescribing systems and drug utilization systems in place to assist the health care provider to provide optimal pharmaceutical care for these patient groups."

Of the total adverse drug events identified in the study, one was fatal, 31 (6 percent) were life-threatening, 206 (38 percent) were serious and 308 (56 percent) were significant, according to the report. The study also identified 188 potential adverse drug events or "near misses," 80 percent of which were associated with the use of the blood thinner, warfarin. Interestingly, more severe adverse drug events were more likely to be preventable than less serious ones, but the reason is unclear.

"Clearly this offers an incredible opportunity to improve meaningfully on the health of a very vulnerable patient population," said Gurwitz. Currently there are over 1.5 million residents of U.S. nursing homes.

Psychoactive drugs (antipsychotics, antidepressants, sedatives and hypnotics) and anticoagulants were the most common medications associated with preventable adverse drug events (oversedation, confusion, hallucinations, delirium, falls and bleeds). More than 36 percent of the nursing home residents used antidepressants, 24 percent used sedatives/hypnotics and 17 percent used antipsychotic medications. Imprecise use of psychoactive medications in nursing homes has long been a concern, the authors of the study noted.

The most frequent causes of preventable adverse drugs events were associated with drug orders by health care providers (47 percent) and when caregivers failed to adequately monitor residents (49 percent). Among the ordering errors, wrong doses were the most common problem followed by ordering drugs with harmful interactions, and wrong choices of drugs. Most common among monitoring errors was inadequate lab monitoring of drug therapies and failure or delay in responding to symptoms or signs of drug toxicity.

"This study points out that it's not just a small list of so-called 'bad drugs' in the elderly that we need to be concerned about, it's the whole range of drugs," Gurwitz said. "However, we have identified some drug categories that appear to cause more problems than others. We're not saying people shouldn't be on these drugs. We're saying that sometimes providers are not monitoring residents appropriately and are missing signals that patients are experiencing adverse effects from drugs."

If the study's findings are generalizable, an average-sized U.S. nursing home (106 beds) will have at least 24 adverse drugs events and eight "near misses" per year, according to the report. If the findings are extrapolated to the 1.5 million U.S. nursing home residents, then at least 350,000 adverse drug events occur every year and more than half are preventable. The authors consider these estimates to be conservative.

The report recommended:

Enhanced surveillance and reporting systems for adverse drug events and medication errors occurring in the nursing home setting;

Continued educational efforts relating to optimal use of drug therapies in the frail elderly patient population; and

A report from the Institute of Medicine published earlier this year ("To Err is Human") made similar recommendations. Data from several sources indicate substantial patient morbidity and mortality as a result of hospitals' medication-related errors, with estimates ranging from 40,000 to 100,000 deaths per year.

The Massachusetts nursing home study, funded by the National Institute on Aging, is part of an ongoing series of studies being performed by the investigators. The NIA, with the Agency for Healthcare Research and Quality, is also currently funding a study to identify strategies to improve the safety of medication use in the ambulatory geriatric patient population. That project is taking place among the senior patient population cared for in the Fallon Healthcare System in Worcester, Massachusetts.

In July 2000, Gurwitz and colleagues began translating their research findings into practice. They are examining the impact of computerized physician ordering systems for reducing medication errors in two large long-term care facilities: Baycrest Centre for Geriatric Care in Toronto and Masonicare in Wallingford, Conn. The three-year study is funded by the Agency for Healthcare Research and Quality.

Physician order entry programs can alert prescribers of medications to potential problems such as excessive doses based on a patient's poor kidney function, allergies, or a dangerous interaction with a drug the patient is already receiving. These programs can also cue health care providers to monitor certain patients more closely for early signs of adverse drug events.

"We're interested in intervening and educating health care providers at the time when a drug is ordered," Gurwitz said. "If we prove physician order entry works in these model facilities, it might lead to health care policy changes to encourage widespread use this technology in all U.S. nursing homes." Such technologies, which assist in the precise prescribing of drugs, have already been shown to prevent serious medication errors in hospital settings.

The NIA, part of the National Institutes of Health at the Department of Health and Human Services, leads the federal effort supporting and conducting research on aging and the special medical, social and behavioral issues of older people. A substantial part of NIA's research involves ways to prevent frailty and reduce disability with age.